A touch panel is a device for inputting information by performing a touch operation (hereafter, referred to as touch) on the characters or a particular location on the display screen through use of a user's finger, a stylus pen and the like without using an input device like a keyboard or a mouse. The touch panel is used in mobile electronic equipments like PDA, a mobile terminal, a variety of electric home appliances, an automatic teller machine, etc.
When multiple objects approach or touch the touch panel by means of the finger and stylus pen, the touch panel is able to simultaneously detect the multiple objects and to detect the shapes of the objects in more detail. To use this ability, it is necessary to measure, identify and distinguish between many kinds of the objects capable of approaching or touching the touch panel at the same time. However, devices equipped with a conventional touch panel (including their support software and/or circuits) cannot stably measure, identify, and distinguish between the objects. For example, in a case where two touch panels are provided, this has a significantly reduced space-efficiency. Besides, in a device equipped with a single touch panel, the user may be enabled to switch a finger mode or a stylus mode by adding a separate input-mode conversion button or conversion menu. However, the separate input-mode conversion button requires a high cost and the device becomes more complicated and has a larger volume. Also, regarding the conversion menu, it is very troublesome to enter a desired menu and to change the input mode.